Not turning over/strange tach behavior
03-08-2012, 11:01 AM
#1
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Not turning over/strange tach behavior
Hello,
Edited for clarity (ty Ben)
My car hasnt been starting but as of a few weeks ago it was turning over so I recently purchased a used, working(I was told its a working unit, but I can not verify) DME unit and put it in my 86 951. I swapped out the DME computer because I had fuel pressure and tach bounce while cranking, but the car just wouldnt start. Not sure about spark. After installing the "new" DME computer, I connected the car to a jump starter--I am well aware this is frowned upon--since the battery of course had lost power. I try to start the car and it does not crank at all now, I believe it should still crank even without a DME, what should I look for?
Also, after trying to start it, and releasing the ignition to "ON" position, the tach jumps to 4k and just stays there until I move the key back to the off position, then it returns back to 0
It wont bounce back up until I try to start the car again.. not sure if anyone has seen that before or knows what it means
Ive tried 2 DME Relays and fuel jumper...car wouldnt start with those conditions, but now that it wont even crank Im more concerned
Edited for clarity (ty Ben)
My car hasnt been starting but as of a few weeks ago it was turning over so I recently purchased a used, working(I was told its a working unit, but I can not verify) DME unit and put it in my 86 951. I swapped out the DME computer because I had fuel pressure and tach bounce while cranking, but the car just wouldnt start. Not sure about spark. After installing the "new" DME computer, I connected the car to a jump starter--I am well aware this is frowned upon--since the battery of course had lost power. I try to start the car and it does not crank at all now, I believe it should still crank even without a DME, what should I look for?
Also, after trying to start it, and releasing the ignition to "ON" position, the tach jumps to 4k and just stays there until I move the key back to the off position, then it returns back to 0
It wont bounce back up until I try to start the car again.. not sure if anyone has seen that before or knows what it meansIve tried 2 DME Relays and fuel jumper...car wouldnt start with those conditions, but now that it wont even crank Im more concerned
Last edited by thr; 03-08-2012 at 12:30 PM.
03-08-2012, 12:20 PM
#2
Burning Brakes
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More info needed. Why did you swap out your DME? You mean the actual DME/ECU, not the DME relay, right?
Also, try and use concrete terms. Cranking is good, we know what that means. Turn over? You mean more cranking, or 'turn over and start running on it's own'?
Tach jumps to 4k and stays there... is it there now? does it reset? Try and search for basic no-start issues
DME Relay
Crank/Ref Sensor + Harness
Getting spark and fuel?
Also, try and use concrete terms. Cranking is good, we know what that means. Turn over? You mean more cranking, or 'turn over and start running on it's own'?
Tach jumps to 4k and stays there... is it there now? does it reset? Try and search for basic no-start issues
DME Relay
Crank/Ref Sensor + Harness
Getting spark and fuel?
03-09-2012, 11:59 AM
#4
Rennlist Member
Sounds like you have multiple issues. You have to start by getting a fully charge (and good) battery in there so the motor will crank (and whether your battery is bad or just being drained excessively by something). Not sure what you mean by jump starter, but suffice to say most external chargers don't have the power needed to crank the motor if the battery is dead-dead...
03-15-2012, 11:24 AM
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One more question/observation before buying myself a new battery,
I connected the car with jumper cables to my trucks battery (while the truck was running) and I still did not hear a click and the starter motor did not turn over...Shouldnt the jumper cables from my trucks battery provide enough amps to the Porsche to get the starter moving if there were no other problems?
I connected the car with jumper cables to my trucks battery (while the truck was running) and I still did not hear a click and the starter motor did not turn over...Shouldnt the jumper cables from my trucks battery provide enough amps to the Porsche to get the starter moving if there were no other problems?
